Level measuring system using admittance sensing
AssigneeDrexelbrook Controls, Inc.
InventorsWilliam S. Wright, Kenneth M. Loewenstern
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Abstract
A transmitting system including an admittance sensing probe having sensing elements adapted to sense both the composition and the level of materials. The probe is coupled to admittance responsive networks forming part of a common oscillator which generate admittance signals representing the level and composition of the material. A remotely located power supply provides current to the transmitters through two pairs of lines, and the output currents of the transmitters represent the level and composition of the materials.
Claims12
In a transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current;
- said transmitter means comprising:
- an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material;
- p1 a single oscillator;
- a first admittance sensing network coupled to said first sensing element and said oscillator;
- a second admittance sensing network coupled to said second sensing element and said oscillator;
- and
- output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the condition and composition of said material respectively.
A transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current, said transmitter means comprising:
- an admittance sensing means including a first admittance sensing element and a second admittance sensing element;
- a single oscillator including,
- a first admittance sensing network including admittance associated with said first sensing element;
- a second admittance sensing network including admittance associated with said second sensing element;
- and
- output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the admittance sensed by said first sensing element and said second sensing element.
In a transmitter system comprising a power supply and a load at one location and transmitter means at another location interconnected by a plurality of transmission lines carrying signals;
- said transmitter means comprising:
- an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material;
- a single oscillator;
- a first admittance sensing network coupled to said first sensing element and said oscillator;
- a second admittance sensing network coupled to said second sensing element and said oscillator;
- and
- output means coupled to said first and said second admittance sensing networks for varying the signals in said plurality of transmission lines in response to the condition and composition of said material respectively.
Dependencies are inferred from the claim text.